This invention relates generally to non-volatile memories and particularly to a technique for assuring the integrity of data in a non-volatile memory.
Non-volatile memories do not require an active source of power to retain their contents (data). The invention in particular is directed to a so-called EAROM (electrically alterable read only memory) which is a non-volatile memory that may be programmed and reprogrammed. Such memories are commonly used in television receivers to retain certain tuning information, for example, a viewer's favorite channels, AFC potentials, band switching voltages and the like. The EAROM will retain its memory contents for many thousands of years without application of outside power, but its data is subject to corruption in the event the memory operating voltage and reset voltage are not properly correlated. The reset voltage has an active or effective range from a reset voltage low to a reset voltage high, and it is imperative that the operating voltage be applied to the memory before the reset voltage is in its active range to avoid corruption of the data in the memory.
The present invention circuit is utilized in a small screen portable color television receiver that can operate from a 12 volt automobile or deep cycle type battery and which has a provision for an AC supply voltage. In such a receiver, it is imperative that weight and size be minimized. The reset circuit of the invention requires very little additional size, cost or power.